Sealing gap

ABSTRACT

The invention relates to a sealing cap ( 11 ), for openings and containers. The valve arrangement ( 15 ) comprises an axiallly displaceable valve body ( 17 ), which is held in the direction of the container interior by means of a spring ( 22 ) against a first sealing seat ( 34 ), on the cap interior. The valve arrangement ( 15 ) comprises one single valve body ( 17 ), provided with a first axially effective sealing surface arrangement ( 20 ) and a second radially effective sealing surface arrangement ( 21 ). The axially effective sealing surface arrangement ( 20 ) co-ordinates with an axial seal seat ( 34 ), surrounding a defined opening ( 32 ), connecting to the container interior on the cap inner part ( 14 ). The radially effective sealing surface arrangement ( 21 ) co-ordinates with a first radial counter sealing surface ( 61, 62 ), comprising a bypass ( 39 ), for the first flow connection and a second radial counter sealing surface ( 61 ), comprising a safety relief opening ( 69 ), for the second flow connection.

[0001] The present invention relates to a sealing cap for openings ofcontainers, especially of motor-vehicle radiators, as genericallydefined by the preamble to claim 1.

[0002] In one such sealing cap, known from German Patent Disclosure DE197 53 592 A1, the valve arrangement has two valve bodies, of which, inthe position of repose, the first valve body rests directly on a sealingseat of the inner cap part under spring loading, and the second valvebody is pressed against a further compression spring by thespring-loaded first valve body. The two-stage opening and closing of theflow connections is achieved by providing that the first valve body islifted by means of the second valve body from its sealing seat on theinner cap part if the first limit value is exceeded; that when thesecond limit value is reached, the second valve body presses against afurther sealing seat of the inner cap part and thus closes the firstflow connection again; and that for the safety stage, an intermediatevalve body disposed between the first and second valve bodies lifts withits sealing seat from a sealing face of the second valve body.

[0003] In terms of its valve arrangement, a sealing cap of this kind iscomplicated structurally, in terms of production, and in terms ofassembly because of the many components.

[0004] From German Patent DE 41 07 525 C1, a sealing cap is also knownthat provides for a two-stage pressure equalization of the closecontainer that may become necessary. In this sealing cap, the valvearrangement also has two valve bodies, which are internested in oneanother; the second valve body is pressed against a sealing seat on theinner cap part by the spring loading of the first valve body. In thisarrangement, when the first limit value of the internal containerpressure is exceeded, the second valve body lifts, carrying the firstvalve body with it, from its sealing seat on the inner cap part, andwhen the second limit value is reached presses against an opposedsealing face of the inner cap part again. In the safety stage, the firstvalve body is lifted from the second valve body.

[0005] In the valve arrangement of this known sealing cap, the samedisadvantages arise as in the sealing cap described earlier above, andfurthermore there is the problem that the sealing seats and sealingfaces of the two valve bodies and of the inner cap part, along with theaxial travel of the second valve body, must be adapted to one anotherwithin narrow tolerances.

[0006] It is therefore the object of the present invention to create asealing cap of the type defined at the outset whose valve arrangement issimplified structurally and in terms of production and assembly.

[0007] For attaining this object in a sealing cap of the type definedabove, the characteristics recited in claim 1 are provided.

[0008] By means of the provisions of the invention, it is attained thatconsiderably fewer components are needed for the valve arrangement ofthe sealing cap without having to accept disadvantages in terms of thetwo-stage action upon pressure equalization. Moreover, specialprovisions for tolerance-bound adaptation become unnecessary. Theindividual components are structurally simpler and can be produced andput together more economically.

[0009] In a preferred exemplary embodiment, the characteristics of claim2 are provided, so that a single sealing element suffices.

[0010] An advantageous feature of the axial sealing seat will becomeapparent from the characteristics of claim 3.

[0011] With the characteristics of claim 4, an advantageous feature ofthe first radial counterpart sealing face is attained in such a way thatthe inner wall of the inner cap part is immediately available for thispurpose. If the provisions of claim 5 and/or claim 6 are also provided,it is attained that the closure of the flow connection in the region ofthe bypass is accomplished primarily by the presence of liquid coolant,rather than by the elevated gas pressure, because whenever liquidcoolant is present at the inlet to the bypass, a head pressure builds upthat moves the valve body farther in the axial direction, thuspreventing an ejection of liquid coolant. In other words, upon anincrease in the internal container pressure, the air cushion locatedabove the liquid coolant can escape in this way and contribute to apressure equilibrium until such time as it has been reduced and theliquid coolant is present.

[0012] An advantageous feature of the radially effective sealing facearrangement will become apparent from the characteristics of claim 7and/or the characteristics of one or more of claims 8-10.

[0013] Advantageously, the valve body is guided on the inner cap part inaccordance with the characteristics of claim 11 and/or claim 12.

[0014] To simplify assembly, the inner cap part is divided in two inaccordance with the characteristics of claim 13.

[0015] With the characteristics of one or more of claims 14-16, anadvantageous disposition of a negative-pressure valve body in thesealing cap is achieved.

[0016] From German Patent Disclosure DE 197 32 885 A1, a sealing capwith safety locking for openings of containers is also known. Thissafety locking makes it possible, when overpressure prevails in thecontainer, to prevent the sealing cap from coming unscrewed,specifically by providing that the sealing cap is blocked nonrotatablyrelative to the fill nozzle on the container. This known safety lockinguses an axially movable insert, which surrounds the inner cap part orits valve arrangement and is as a result exposed directly to theoverpressure prevailing in the container, because its inner bottom islocated in the opening of the fill nozzle. This axially movable insertis axially movable but is retained nonrotatably in a tubularsupplementary inner part which is seated nonrotatably in the fill nozzleof the container and relative to which the sealing cap is rotatable.When overpressure occurs in the container, the insert is moved axiallyin the direction of the sealing cap and engages it nonrotatably. Theresult is a blockage of rotation of the sealing cap via the insert andthe supplementary inner part with the fill opening of the container.

[0017] The provisions in this reference for torsion prevention or safetylocking are complicated both structurally and because of the number ofcomponents to be used. Moreover, the axially movable insert and thetubular supplementary inner part not only increase the diameter of theinner cap part of the sealing cap but also reduce the effective area ofthe valve arrangement of the sealing cap, with adverse effects on theresponse behavior of the valve arrangement.

[0018] To provide a remedy to this, the characteristics of claim 17 areprovided in a sealing cap of this kind, so that its torsion preventionupon overpressure can be established in a way that is simpler bothstructurally and in terms of production and is therefore moreeconomical. This is because, as a result of the direct derivation ofmotion from the sole valve body, no additional components are necessary;instead, idle travel is achieved between the closure element thatcarries the thread or the like and the grip element or actuating handleupon overpressure. This idle travel connection at overpressure has thesubstantial advantage, compared with blocking the sealing cap uponoverpressure, that the activation of the torsion prevention becomesvisually noticeable, thus precluding possible exertions of force in theevent of blockage.

[0019] Further space is saved for the valve arrangement whenever thecharacteristics of claim 18 are provided.

[0020] With the characteristics of claim 19, a reinforcement of theaxial motion of the coupling insert is obtained. For guiding the valvebody and the coupling insert in the back and forth motion, thecharacteristics of claim 20 are advantageously provided. It may beexpedient to embody the guide element in accordance with thecharacteristics of claim 21. The sleeve element can thus actively returnthe coupling insert from its disengaged position to its engaged positionin conjunction with the spring coupling. The characteristics of claim 22are expediently provided in this respect as well.

[0021] From the characteristics of one or more of claims 23-26,preferred features and dispositions of the compression springs of thespring coupling of the valve body, guide element and inner cap part arealso obtained.

[0022] In a further feature of the engagement and disengagementconnection of the coupling insert, the characteristics of claim 27 andoptionally claim 28 are provided.

[0023] Further details of the invention can be learned from the ensuingdescription, in which the invention is described and explained in termsof the exemplary embodiments shown in detail in the drawing. Shown are:

[0024]FIG. 1, in a longitudinal sectional view, anoverpressure/negative-pressure valve arrangement of a sealing cap for amotor-vehicle radiator, in the closed outset position, in a firstexemplary embodiment of the present invention;

[0025]FIG. 2, in a somewhat enlarged half section, the sealing cap ofFIG. 1 in a position after a first limit value of the internal containerpressure is exceeded;

[0026]FIG. 3, a view corresponding to FIG. 2, but in a position after asecond limit value of the internal container pressure is reached, or afluid head pressure is applied;

[0027]FIG. 4, a view corresponding to FIG. 2, but in a position after athird or safety limit value of the internal container pressure isexceeded;

[0028]FIG. 5, a longitudinal sectional view of a sealing cap for amotor-vehicle radiator with an overpressure/negative-pressure valvearrangement and torsion prevention in the closed or nonactivated outsetposition, in a second exemplary embodiment of the present invention;

[0029]FIG. 6, a view corresponding to FIG. 5, but in a position duringthe buildup of an overpressure in the container interior;

[0030]FIG. 7, a view corresponding to FIG. 5, in a position after afirst limit value is exceeded but before a second limit value of theinternal container pressure is reached;

[0031]FIG. 8, a position corresponding to FIG. 5, but in a positionafter a third or safety limit value of the internal container pressureis exceeded; and

[0032]FIG. 9, a view corresponding to FIG. 5, but in a position afterthe normal pressure is reached in the container interior and before thetorsion prevention is reversed or undone.

[0033] The sealing cap 11 shown in FIGS. 1-4, for instance for amotor-vehicle radiator, in a manner not shown has an outer cap part,which is provided with an actuating handle and on which an inner cappart 14 with a negative-pressure/overpressure valve arrangement 15 isretained. In the position for use, the sealing cap 11 is fixed on aradiator neck, not shown, for instance being screwed onto it. The innercap part 14 protrudes in the radiator neck in the direction of theradiator interior. An O-ring 16 seals the inner cap part 14 off from theradiator neck wall. The overpressure part of the valve arrangement 15 isembodied in two stages and in a first overpressure stage serves toprevent the radiator from boiling dry, while in a second overpressurestage, security against damage to the radiator system from excessiveoverpressure is assured.

[0034] The overpressure part of the valve arrangement 15 has a singlevalve body 1, which is axially movable between two terminal positionsinside the inner cap part 14. The valve body 17 has a profiled ring seal18, which has both an axially effective sealing face arrangement 20 anda radially effective sealing face arrangement 21. The valve body 17 isaxially prestressed inward in the direction of the container interior bymeans of a compression spring 22 braced on the inner cap part 14.

[0035] The inner cap part 14 is embodied in two parts and is thuscomposed of an inner, upper element 25 and an outer main element 26,which is retained in the outer cap part in a manner not shown and inwhich the inner, upper element 25 is fixed in sealed fashion. The inner,upper element 25 has a coaxial guide ring attachment 27, which protrudesinward from the top 28 of the element 25. This guide ring attachment 27receives one end of the compression spring 22, which is braced on theinside of the top 28. On the outer circumference, the guide ringattachment 27 serves to provide axial guidance of the valve body 17. Atthe level of the guide ring attachment 27, the inner cap part 14 isprovided with radial outflow openings 29 on the outer circumference.Between the inner, upper element 25 and the main element 26, an O-ring24 is provided for the sake of tight connection.

[0036] The main element 26 of the inner cap part 14, on its bottom 31,has a flowthrough opening 32, in this case coaxial, which forms acommunication between the container interior and the interior of theinner cap part 14. The flowthrough opening 32 is surrounded coaxially byan annular attachment 33 that protrudes toward the inside of the innercap part 14, and its free annular face end forms a sealing seat 34 forthe axially effective sealing face arrangement 20 of the profile ringseal 18 of the valve body 17. Between the outer circumference of theannular attachment 33 and the inner circumference of the main element26, an annular chamber 36 remains in this region. Above this annularchamber 36, the main element 26 of the inner cap part 14 has an annulargroove 37, which is open axially outward and in which an annular insert38 is received that contains or forms a U-shaped throttling conduit 39.In the exemplary embodiment shown, the U-shaped throttling conduit 39 isprovided at a point on the circumference of the main element 26 of theinner cap part 14. The throttling conduit 39 has two radial conduitparts 41 and 42, axially spaced apart from one another, which are joinedtogether by an axial conduit part 43 that is located between theapplicable inner circumference region of the main element 26 and theapplicable outer circumference region of the annular insert 38. Theconduit parts 41 and 42 are formed here by radial grooves cut into theannular insert 38, while the conduit part 43 is formed by an axialgroove cut into the main element 26.

[0037] The one-piece valve body 17 has a main part 46, which is radiallystepped in the axial direction and which carries the profile ring seal18, and a guide part 47, remote from the profile ring seal 18, which ishollow-cylindrical and is guided on the guide ring attachment 47, whichit grips, of the inner cap part 14. The compression spring 22 is bracedon an inner shoulder, remote from the profile ring seal 18, of the valvebody 17.

[0038] The profile ring seal 18 is secured to a stepped outercircumferential region of the valve body 17. The axially effectivesealing face arrangement 20 of the profile ring seal 18 is arched,viewed in cross section, and has a radially outer sealing face 51, aradially middle sealing face 52, and a radially inner sealing face 53.The radially inner sealing face 53 cooperates with a negative-pressurevalve body 71 to be described hereinafter; the radially middle sealingface 52, in the position of repose of the valve arrangement 15, rests onthe sealing seat 34 of the inner cap part 14; and the radially outersealing face 51 rests on the bottom of the annular chamber 36. Bycomparison, the radially effective sealing face arrangement 21 has twosealing faces 56 and 57 which are disposed at a defined axial spacingand between which a clearance 58 is provided. Both the upper sealingface 56 and the lower sealing face 57, which merges with the radiallyouter sealing face 51, rest sealingly on the inner wall 61 and/or 62,embodied as a sealing seat, of the main element 26 of the inner cap part14 and of the annular insert 38, respectively.

[0039] In the center of the valve body 17, an opening 66 is provided,which is closed on the side toward the radiator interior by thenegative-pressure valve body 71 of the valve arrangement 15. Thenegative-pressure valve body 71 protrudes with its main part 72 throughthe central opening 66 and is acted upon in the end region thereof by acompression spring 67, which is braced on one end on a shoulder of themain part 72 and on the other on the outer face of the inner shoulder ofthe valve body 17, on which the compression spring 22 also rests. Inthis way, the negative-pressure valve body 71 is pressed sealingly withits annular sealing seat 73 against the radially inner sealing face 53of the axially effective sealing face arrangement 20 of the profile ringseal 18 of the valve body 17.

[0040] In the position of repose, or outset operating position, shown inFIG. 1, in which a first limit value of the internal container pressurehas not yet been exceeded, any flow connection between the containerinterior and container exterior is closed as a result of the sealingcontact of all the sealing faces 51-53 of the axially effective sealingface arrangement 20 of the profile seal 18 of the valve body 17 againstthe respective sealing seats 36, 34, 73 of the inner cap part 14 and ofthe negative-pressure valve body 71, respectively. In other words,through the flowthrough opening 32, the pressure prevailing in theinterior of the container is present in the form of the air cushion,located above the liquid radiator medium, at both the profile ring seal18 of the valve body 17 and the underside of the negative-pressure valvebody 71.

[0041] If the internal container pressure increases above thepredetermined first limit value, then the valve arrangement 15 of thesealing cap 11 reaches the operating state shown in FIG. 2, in which thevalve body 17, counter to the action of its compression spring 22, liftswith its radially middle sealing face 52 from the sealing seat 34, andthe profile ring seal 18 reaches the region of the annular insert 38, insuch a way that the two radial sealing faces 56 and 57 of the radiallyeffective sealing face arrangement 21 of the profile ring seal 18 of thevalve body 17 are located above and below the radial conduit parts 41and 42, respectively, and thus open the throttling conduit 39 on bothends. In this operating state, an equilibrium has been establishedbetween the action of the internal container pressure and the contraryaction of the compression spring 22. Thus a first flow connectionbetween the container interior and the container exterior is opened,leading from the flowthrough opening 32 via the U-shaped throttlingconduit 39 to the outflow openings 29. As a result, air from the aircushion located above the liquid radiator medium can flow to the outsideand compensate for or reduce the overpressure. If as a result theoverpressure is reduced to below the first limit value, then the valvebody 17 returns to sealing contact with the axial sealing seat 34 of theinner cap part 14.

[0042] Conversely, if the internal container pressure increases furthereven during or after the elimination of the air cushion, and if thiscauses liquid radiator medium to reach the underside of the profile ringseal 18 and of the negative-pressure valve body 71, then the result,because of the very narrow throttling conduit 39 (with a cross-sectionalsize on the order of a few hundredths of a millimeter) is a backup ofthe liquid radiator medium at the entrance to the lower radial conduitpart 42 of the throttling conduit 39, and thus a head pressure at thefull-surface undersides of the profile ring seal 18 andnegative-pressure valve body 71. This head pressure causes an axialmotion of the valve body 17 onward, counter to the action of thecompression spring 22, so that in the operating state of FIG. 3, thethrottling conduit 39 is closed again at the upper radial conduit part41. In this operating state, the throttling conduit 39 is thus closed insuch a way that its upper radial conduit part 41 opens into theclearance space 58 between the two sealing faces 56 and 57 of theprofile ring seal 18. An ejection of liquid radiator medium is thusprevented. If the internal container pressure is reduced by cooling downof the motor-vehicle radiator, and the liquid radiator medium is thusreturned, then the valve body 17 can also be restored under the actionof its compression spring 22, so that the throttling conduit 39 opensagain, and a further pressure buildup can take place.

[0043] Conversely, if the internal container pressure continues toincrease, then when an upper (safety) pressure limit value is exceeded,the valve body 17 is lifted farther, counter to the compression spring22 loading it, so that windows 69 located at certain circumferentialregions in the wall of the inner cap part 14, which communicate with thecontainer interior (FIG. 4) in a manner not shown, are opened. In thisstate, as before, the upper conduit part 41 opens into the clearancespace 58, which has no communication with the outflow openings 29. Thisupper terminal position of the valve body 17 is defined by the contactof an inner step 48 of the valve body 17 with the free annular face endof the guide ring attachment 27 of the inner cap part 14. As a result,the aforementioned overpressure can be reduced via a second flowconnection, after which a corresponding restoration of the valve body 17over the various operating states can occur.

[0044] The outset position shown in FIG. 1 is assumed by the valvearrangement 15 whenever the internal pressure in the radiator is movingbetween a negative-pressure limit value and the first overpressure limitvalue. Such pressure conditions exist for instance in a vehicle that hasbeen parked for a relatively long time, or during vehicle travel whenthere is adequate cooling of the coolant in the radiator interior by therelative wind and/or by a fan. If after a relatively long trip thevehicle is stopped after a relatively long trip, there can be aresultant pressure increase in the radiator interior, allowing thecontents of the radiator (air or water or water vapor) to flow to thevalve arrangement 15. If the coolant volume expands from thisafter-heating effect to such an extent that the container volume isexceeded, this would necessarily cause the expulsion of coolant. Thisunwanted effect is prevented, in the manner described above, because theoperating state of the valve arrangement 15 as shown in FIG. 3 isestablished. If in this operating state a further uncontrolled pressurerise in the cooling system occurs, then leaks and other adverse effectsresulting from an overload on the radiator container and/or the hoseconnection points must be averted. These effects are averted by thesecond valve stage, in the state shown in FIG. 4, which limits thecontainer pressure to a predetermined safety pressure value.

[0045] If negative pressure prevails in the radiator interior, and thispressure falls below a predetermined negative-pressure limit value, thenbeginning at the operating state shown in FIG. 1, the negative-pressurevalve body 71 with its sealing seat 73 is lifted from the radially innersealing face 53 of the profile ring seal 18 of the valve body 17 towardthe radiator interior. The lowering of the negative-pressure valve body71 takes place counter to the prestressing force of the compressionspring 67, so that in a manner not shown, a third flow connectionbetween the radiator interior and the radiator exterior opens.

[0046] The sealing cap 111, for instance for a motor-vehicle radiator,shown in FIGS. 5-9 has an outer cap part 110, which is provided with agrip element or actuating handle 112, and on whose closure element 113,embodied here as a screw-on element, an inner cap part 114 is keptsuspended and retained relatively rotatably with anegative-pressure/overpressure valve arrangement 115. In the positionfor use, the sealing cap 111 is fixed, for instance being screwed on, toa radiator neck, not shown. The inner cap part 114 protrudes within theradiator neck in the direction of the radiator interior. An O-ring 116seals off the inner cap part 114 from the radiator neck wall. In thetwo-part outer cap part 110, the caplike actuating handle 112 is axiallyfixed on the screw-on element 113 but is rotatable in thecircumferential direction. This rotatability is blocked, at normalpressure in the radiator interior, by an axially movable coupling insert180 for screwing and unscrewing the sealing cap 111.

[0047] The overpressure part of the valve arrangement 15 is embodied intwo stages and in a first overpressure stage serves to prevent theradiator from boiling dry, while in a second overpressure stage,security against damage to the radiator system from excessiveoverpressure is assured.

[0048] The overpressure part of the valve arrangement 115 has a singlevalve body 117, which is axially movable between two terminal positionsinside the inner cap part 114. The valve body 117 has a profiled ringseal 118, which has both an axially effective sealing face arrangement120 and a radially effective sealing face arrangement 121. The valvebody 117 is axially prestressed inward in the direction of the containerinterior by means of a compression spring 122 braced on the inner cappart 114.

[0049] The inner cap part 114 is embodied in two parts and thus iscomposed of an inner element 125 and an outer, main element 126, whichis kept suspended in the screw-on element 113 of the outer cap part 110and in which the inner element 125 is fixed in sealed fashion. The innerelement 125 is approximately hood-shaped, with an axial opening in thehood bottom 128, on whose inside one end of the compression spring 122is braced. Approximately at the level of the lower end of the outer cappart 110, the inner cap part 114 is provided on its outer circumferencewith radial outflow openings 129. Between the inner element 125 and themain element 126, an O-ring 124 is provided for the sake of tightconnection.

[0050] The main element 126 of the inner cap part 114, on its bottom131, has a flowthrough opening 132, in this case coaxial, which forms acommunication between the container interior and the interior of theinner cap part 114. The flowthrough opening 132 is surrounded coaxiallyby an annular attachment 133 that protrudes toward the inside of theinner cap part 114, and its free annular face end forms a sealing seat134 for the axially effective sealing face arrangement 120 of theprofile ring seal 118 of the valve body 117. Between the outercircumference of the annular attachment 133 and the inner circumferenceof the main element 126, an annular chamber 136 remains in this region.Above this annular chamber 136, between the lower annular face end ofthe inner element 125 and a setback in the main element 126 of the innercap part 114, an annular insert 138 is received that contains or forms aU-shaped throttling conduit 139. In the exemplary embodiment shown, theU-shaped throttling conduit 139 is provided at a point on thecircumference of the inner cap part 114. The throttling conduit 139 hastwo axially spaced-apart radial conduit parts 141 (adjacent to the innerelement 125) and 142 (adjacent to the setback in the main element 126),which are joined together by an axial conduit part 143 that is locatedbetween the applicable inner circumference region of the main element126 and the applicable outer circumference region of the annular insert138. The conduit parts 141, 142 and 143 are formed here by radial andaxial grooves cut into the annular insert 138.

[0051] The one-piece valve body 117 has a main part 146, which isradially stepped in the axial direction and which carries the profilering seal 118, and on which, remote from the profile ring seal 118, aguide element 147 is seated, which is hollow-cylindrical and engages thehollow coupling insert 180. The compression spring 122 is braced on aradial outer shoulder of the main part 146 of the valve body 117.

[0052] The profile ring seal 118 is secured to the inside face of astepped outer circumferential region of the valve body 117. The axiallyeffective sealing face arrangement 120 of the profile ring seal 118 isarched, viewed in cross section, and has a radially outer sealing face151, a radially middle sealing face 152, and a radially inner sealingface 153. The radially inner sealing face 153 cooperates with anegative-pressure valve body 171 to be described hereinafter; theradially middle sealing face 152, in the position of repose of the valvearrangement 115, rests on the sealing seat 134 of the inner cap part114; and the radially outer sealing face 151 rests on the bottom of theannular chamber 136. By comparison, the radially effective sealing facearrangement 121 has two sealing faces 156 and 157 which are disposed ata defined axial spacing and between which a clearance 158 is provided.Both the upper sealing face 156 and the lower sealing face 157, whichmerges with the radially outer sealing face 151, rest sealingly on theinner wall 161 and/or 162, embodied as a sealing seat, of the mainelement 126 of the inner cap part 114 and of the annular insert 138,respectively.

[0053] The guide element 147, seated with an inner end on the outer faceof the inner shoulder of the valve body 117, protrudes with its otherend into the central through opening of the coupling insert 180. Thecoupling insert 180 and guide element 147 are rotatable relative to oneanother and displaceable axially to one another. The axialdisplaceability is limited, as FIG. 5 shows, by shoulders 181, 182resting on one another, in such a way that the guide element 147 andcoupling insert 180 always engage one another. The guide element 147 isembodied in sleevelike fashion, and its outer wall is stepped on theinner end, toward the valve body 147, to form contact shoulders for anaxial spring coupling arrangement. The spring coupling arrangement has afirst, inner helical compression spring 183, which is prestressedbetween the coupling insert 180 and the guide element 147, and a second,by comparison outer, helical compression spring 184, which is braced onone end on the guide element 147 and on the other in the inner element125 of the inner cap part 114. These two helical compression springs 183and 184 are surrounded by the helical compression spring 122 that actson the valve body 117.

[0054] The axially displaceable coupling insert 180, which with itslower end that fits over the guide element 147 penetrates a centralthrough bore in the inner element 125 of the inner cap part 114, restswith its outer end, of larger outer diameter, in the outset state shownin FIG. 5, inside a recess 186 of a radial flange 187 of the screw-onelement 113 and inside a central annular flange 188 protruding axiallyinward on the actuating handle 112. With the axial flange 188, thecoupling insert 180 is connected constantly nonrotatably to theactuating handle 112, for instance by means of suitable sets ofintermeshing teeth. In the outset position shown in FIG. 5, the couplinginsert 180 is also nonrotatably connected to the radial flange 187 ofthe screw-on element 113, specifically once again via circumferential,axially extending toothing arrangements, not shown. In this way, theactuating handle 112 and the screw-on element 113 are nonrotatablyjoined together in the circumferential direction, so that the sealingcap 111 can be screwed onto the fill neck, not shown, of a container andunscrewed from it by means of the actuating handle 112.

[0055] In the center of the valve body 117, an opening 166 is provided,which on the side toward the radiator interior is closed by thenegative-pressure valve body 171 of the valve arrangement 115. Thenegative-pressure valve body 171 protrudes with its main part 172through the central opening 166 and is acted upon on its end region by acompression spring 167, which is braced on one end on a shoulder of themain part 172 and on the other on the outer face of the inner shoulderof the valve body 117. In this way, the negative-pressure valve body 171is pressed sealingly with its annular sealing seat 173 against theradially inner sealing face 153 of the axially effective sealing facearrangement 120 of the profile ring seal 118 of the valve body 117.

[0056] In the position of repose or outset operating position shown inFIG. 5, in which as yet no overpressure prevails in the containerinterior, any flow connection between the container interior andcontainer exterior is closed as a result of the sealing contact of allthe sealing faces 151-153 of the axially effective sealing facearrangement 120 of the profile seal 118 of the valve body 117 againstthe respective sealing seats 136, 134, 173 of the inner cap part 114 andof the negative-pressure valve body 171, respectively. In other words,through the flowthrough opening 132, the pressure prevailing in theinterior of the container is present in the form of the air cushion,located above the liquid radiator medium, at both the profile ring seal118 of the valve body 117 and the underside of the negative-pressurevalve body 171.

[0057] If the internal container pressure increases to a certain amount,which is above the normal pressure but below a first limit value of theinternal container pressure, then the unscrewing prevention of thesealing cap 111 is activated. As shown in FIG. 6, the valve body 117 ismoved upward, so that the profile ring seal 118 lifts with its middlesealing face 152 from the sealing seat 134. This enlarges the effectivearea acted upon by the overpressure, an area that until now was formedonly by the underside of the negative-pressure valve body 171, aroundthe inner axial face of the profile ring seal 118. This larger effectivearea, for the same pressure, exerts a greater force on the valve body117 and results in a lengthened stroke thereof. As a result of thereciprocating motion of the valve body 117, which however does not yetopen the throttling conduit 139, counter to the action of the firsthelical compression spring 183 and the second helical compression spring184, the guide element 147 is initially axially displaced relative tothe coupling insert 180. Since as a result of this reciprocating motionthe first helical compression spring 183, which is braced on thecoupling insert 180, is prestressed, the coupling insert 180 is axiallydisplaced. As a result of this axial motion outward of the couplinginsert 180 in the direction of the arrow A and up to an inner stop atthe underside of the actuating handle 112, the coupling insert 180, onits larger-diameter end, comes free of the toothing on the screw-onelement 113. This disengagement motion of the coupling insert 180 causesthe actuating handle 112 to revolve idly relative to the screw-onelement 113, so that beyond a certain defined overpressure (in thiscase, 0.3 bar, for instance), unscrewing of the sealing cap 111 is nolonger possible.

[0058] If the internal container pressure increases further, that is,beyond the predetermined first limit value (for instance of 1.4 bar),then the valve arrangement 115 of the sealing cap 111 reaches theoperating state shown in FIG. 7, in which the valve body 117 lifts awayfarther, counter to the action of its compression spring 122, and theprofile ring seal 118 reaches the region of the annular insert 138 insuch a way that the two radial sealing faces 156 and 157 of the radiallyeffective sealing face arrangement 121 of the profile ring seal 118 ofthe valve body 117 are located above and below the radial conduit parts141 and 142, respectively, and thus open the throttling conduit 139 onboth ends. In this operating state, in which the unscrewing preventioncontinues to remain activated, an equilibrium has been establishedbetween the action of the internal container pressure and the contraryaction of the compression spring 122. Thus a first flow connectionbetween the container interior and the container exterior is opened,leading from the flowthrough opening 132 via the U-shaped throttlingconduit 139 to the outflow openings 129. As a result, air from the aircushion located above the liquid radiator medium can flow to the outsideand compensate for or reduce the overpressure. If as a result theoverpressure is reduced to below the first limit value, then the valvebody 117 resumes its sealing contact with the axial sealing seat 134 ofthe inner cap part 114.

[0059] Conversely, if the internal container pressure increases furthereven during or after the elimination of the air cushion, and if thiscauses liquid radiator medium to reach the underside of the profile ringseal 118 and of the negative-pressure valve body 171, then the result,because of the very narrow throttling conduit 139 (with across-sectional size on the order of a few hundredths of a millimeter)is a backup of the liquid radiator medium at the entrance to the lowerradial conduit part 142 of the throttling conduit 139, and thus a headpressure at the full-surface undersides of the profile ring seal 118 andnegative-pressure valve body 171. This head pressure causes an axialmotion of the valve body 117 onward, counter to the action of thecompression spring 122, so that in this operating state for instancewith a pressure of 1.5 bar, at the upper radial conduit part 141, thethrottling conduit 139 is closed again in a manner not shown by theupper radial sealing face 156 of the profile ring seal 118. Theunscrewing prevention continues to be activated. An ejection of liquidradiator medium is thus prevented. If the internal container pressure isreduced by cooling down of the motor-vehicle radiator, and the liquidradiator medium is thus returned, then the valve body 117 can also berestored under the action of its compression spring 122, so that thethrottling conduit 139 opens again, and a further pressure buildup cantake place.

[0060] Conversely, if the internal container pressure continues toincrease, then when an upper (safety) pressure limit value (for instanceof 2 bar) is exceeded, the valve body 117 is lifted farther, counter tothe compression spring 122 loading it, so that axial outflow conduits169, located at certain circumferential regions in the wall of both theannular insert 138 and the inner element 125 of the inner cap part 114,are opened, which are in communication with the outflow opening 129 andtherefore with the container exterior (FIG. 8). In this operating state,as before, the upper conduit part 141 is still closed. This upperterminal position of the valve body 117 is defined by the compressedcompression springs 122, 183, and 184. The unscrewing preventioncontinues to remain activated. As a result, the aforementionedoverpressure can be reduced via a second flow connection, after which acorresponding restoration of the valve body 117 over the variousoperating states can occur by means of the compression spring 122, as isshown in FIG. 9.

[0061]FIG. 9 also shows one possible brief state of the unscrewingprevention, whenever the valve body 117 has returned to its outsetposition and rotation of the actuating handle 112 has occurred while theunscrewing prevention was activated. In that case, it might havehappened that the coupling insert 180 with its toothing failed to comeprecisely above the tooth gaps in the toothing of the unscrewing element113. In order in this case to return the unscrewing prevention from itsactivated state to its deactivated state in accordance with FIG. 5, abrief rotary actuation of the actuating handle 112 suffices; this causesthe outer, second helical compression spring 184, which is underconsiderable prestressing, to move the guide element 147 downward,counter to arrow A. This relaxes the inner, first compression spring183, and the guide element 147, with its outer annular shoulder 181, asa result of contact with the inner annular shoulder 182 of the couplinginsert 180, carries this coupling insert along with it in the directionof arrow A, so that the coupling connection between the actuating handle112 and the unscrewing element 113 is reengaged or comes into effectagain. The overall operating position of FIG. 5 is thus achieved, andthe sealing cap 111 can be unscrewed from the fill neck of the radiatorwithout danger.

[0062] The outset position shown in FIG. 5 is assumed by the valvearrangement 115 whenever the internal pressure in the radiator is movingbetween a negative-pressure limit value and an only very slightoverpressure value, in this case of less than 0.3 bar. Such pressureconditions exist for instance in a vehicle that has been parked for arelatively long time, or during vehicle travel when there is adequatecooling of the coolant in the radiator interior by the relative windand/or by a fan. If after a relatively long trip the vehicle is stoppedafter a relatively long trip, there can be a resultant pressure increasein the radiator interior, allowing the contents of the radiator (air orwater or water vapor) to flow to the valve arrangement 115. If thecoolant volume expands from this after-heating effect to such an extentthat the container volume is exceeded, this would necessarily cause theexpulsion of coolant. This unwanted effect is prevented. If in thisoperating state a further uncontrolled pressure rise in the coolingsystem occurs, then leaks and other adverse effects resulting from anoverload on the radiator container and/or the hose connection pointsmust be averted. These effects are averted by the second valve stage, inthe state shown in FIG. 8, which limits the container pressure to apredetermined safety pressure value.

[0063] If negative pressure prevails in the radiator interior, and thispressure falls below a predetermined negative-pressure limit value, thenbeginning at the operating state shown in FIG. 5, the negative-pressurevalve body 171 with its sealing seat 173 is lifted from the radiallyinner sealing face 153 of the profile ring seal 118 of the valve body117 toward the radiator interior. The lowering of the negative-pressurevalve body 171 takes place counter to the prestressing force of thecompression spring 167, so that in a manner not shown, a third flowconnection between the radiator interior and the radiator exterioropens.

1. A sealing cap (11) for openings of containers, in particular ofmotor-vehicle radiators, having an inner cap part (14) and a first and asecond flow connection between the container interior and the containerexterior, and a valve arrangement (15) for opening and closing the flowconnections, such that when a first limit value for the internalcontainer pressure is exceeded, the first flow connection is opened andis then closed again when a second, higher limit value is reached, andwhen a third limit value of the internal container pressure, which ishigher than both the first and the second limit values of the internalcontainer pressure, is exceeded, the second flow connection is opened,and the valve arrangement (15) has an axially displaceable valve body(17), which is pressed by a spring (22) in the direction of thecontainer interior against a first sealing seat (34) on the inner cappart (14), characterized in that the valve arrangement (15) has a singlevalve body (17), which is provided with a first, axially effectivesealing face arrangement (20) and a second, radially effective sealingface arrangement (21), and the axially effective sealing facearrangement (20) is assigned an axial sealing seat (34), surrounding aconnection opening (32) to the container interior that is predeterminedat the inner cap part (14), and the radially effective sealing facearrangement (21) is assigned a first radial counterpart sealing face(61, 62), having a bypass (39) around the first flow connection, and asecond radial counterpart sealing face (61) having a safety reliefopening (69) of the second flow connection.
 2. The sealing cap of claim1, characterized in that the axially effective sealing face arrangement(20) and the radially effective sealing face arrangement (21) of thevalve body (17) are united in a profiled sealing ring (18).
 3. Thesealing cap of claim 1 or 2, characterized in that the axial sealingseat (34) on the inner cap part (14) is formed by an annular attachment(33), which protrudes from the bottom (31) that is provided with theconnection opening (32).
 4. The sealing cap of at least one of claims1-3, characterized in that the first radial counterpart sealing face isformed by the inner wall (61, 62) of the inner cap part (14), in whichwall, in a first axial region, an annular insert (38) is received, whichforms the bypass (39) around the first flow connection.
 5. The sealingcap of claim 4, characterized in that the bypass is embodied by aU-shaped throttling conduit (39) on at least one circumferential pointof the inner cap part (14).
 6. The sealing cap of claim 5, characterizedin that the annular insert (38) has two radial conduits (41, 42),disposed in axial spacing, which are formed by an axial conduit (43)between the outer face of the annular insert (38) and the inner face ofthe inner cap part (14).
 7. The sealing cap of claims 1 and 6,characterized in that the radially effective sealing face arrangement(21) has two sealing face regions (56, 57), whose axial spacing is lessthan the axial spacing of the two radical conduits (41, 42) of thebypass (39).
 8. The sealing cap of cap of claims 2 and 7, characterizedin that the sealing face regions (56, 57) are formed by acircumferential clearance (58) in the profiled sealing ring (18).
 9. Thesealing cap of at least one of the foregoing claims, characterized inthat the second radial counterpart sealing face is formed by the innerwall (61)of the inner cap part (14), in which the safety relief openings(69) are formed in a second axial region.
 10. The sealing cap of claims4 and 9, characterized in that the two axial regions of the inner wall(61) of the inner cap part (14) overlap.
 11. The sealing cap of at leastone of the foregoing claims, characterized in that the value body (17)has a guide sleeve (47), disposed facing away from the profiled sealingring (18), and the guide sleeve cooperates with a guide ring (27)protruding axially from the inner cap part (14).
 12. The sealing cap ofclaim 11, characterized in that the compression spring (22) that acts onthe valve body (17) is retained inside the guide ring (27).
 13. Thesealing cap of at least one of the foregoing claims, characterized inthat the inner cap part (14) is axially divided in two.
 14. The sealingcap of at least one of the the foregoing claims, characterized in thatthe valve body (17) has a central opening (66), through which anegative-pressure vavle body (71) protudes whose sealing seat (73),surrounding the central opening (66), rests on a further axial sealingface (53) of the valve body (17).
 15. The sealing cap of claim 14,characterized in that the further axial sealing face (53) is part of theaxially effective sealing face arrangement (20) or of the profiledsealing ring (18).
 16. The sealing cap of claim 14 or 15, characterizedin that the negative-pressure valve body (71) prestressed against thefurther axial sealing face (53) of the valve body (17) with the aid of aspring (67) braced on the top side of the valve body (27).
 17. Thesealing cap (111) of at least one of the foregoing claims, characterizedin that an outer cap part (110), on which the outer cap part (14) isretained in suspended fashion, is formed by grip and closure elements(112, 113) that are rotatable relative to one another, and for theirreleaseable connection in a manner fixed against reflective rotation, anaxially movable coupling insert (180) is provided, whose axial motion isderived from the pressure-dependent axial motion of the sole valve body(117).
 18. The sealing cap of claim 17, characterized in that the axillymovable coupling insert (180) is disposed inside the grip element (112)of the outer cap part (110).
 19. The sealing cap of claim 17 or 18,characterized in that an axial spring coupling (103) for disengaementand/or engagement of the coupling insert (180) is provided between theaxially movable coupling insert (180) and the valve body (117).
 20. Thesealing cap of at least one of claims 17-19, characterized in that anaxially movable guide element (147) is provided between the axiallymovable coupling insert (180) and the valve body (117).
 21. The sealingcap of claim 20, characterizd in that the guide element (147) is axiallymovable inside the hollow coupling insert (180) and is retained inamaximal extension position by end stop elements (181, 182).
 22. Thesealing cap of claim 21, characterized in that the guide element (147)and the coupling insert (180) are retained rotatably relative to oneanother.
 23. The sealing cap of at least one of claims 19-22,characterized in that the axial spring coupling (183, 184) surrounds theguide element (147).
 24. The sealing cap of at least one of claims19-23, characterized in that the axial spring coupling has a firsthelical compression spring (183), which is provided between the gudeelement (147) and the coupling insert (180).
 25. The sealing cap of atleast one claims 19-24, characterized in that the axial spring couplinghas a second helical compression spring (183, which is disposed betweenthe guide element (147) and the inner cap part (114).
 26. The sealingcap of one of the claims 23-25, characterized in that the helicalcompression spring (122) that acts on the sole valve body (117)surrounds the compression spring or compression springs (183, 184) ofthe axial spring coupling.
 27. The sealing cap of at least one of theclaims 17-26, characterized in that the axially movable coupling insert(180) is constantly connected in a manner fixed against relativerotation to the grip element (112) of the outer cap part (110) and isaxially movable relative to them and is connectable releasably to theclosure elemrnt (113) of the outer cap part (110) by axial engagementand disengagement in the circumferential direction.
 28. The sealing capof claims 27, characterized in that the releaseable connectability inthe circumferential direction is formed by an axially orientedcircumferential toothing of the closure element (113) and the couplinginsert (180).